1. Technical Field
The present disclosure relates to an airbag, and more particularly, to an airbag with multiple layers of progressive cushioning effect.
2. Description of Related Art
In recent years, owing to the raising of vehicle safety awareness, vehicles are equipped with several airbags for protecting occupants during car collisions.
An airbag generally includes a folded bag body, which can be used together with an inflating module (including sensors, a collision sensor, and an inflator). The principle of the airbag is to sense the collision of a vehicle by using several sensors or a single-point sensor disposed in the vehicle and to determine whether using the collision sensor should deploy the bag body. That is, when a car collision occurs, the sensor(s) will sense the instant acceleration of the collision, and the collision sensor determines whether the instant acceleration exceeds a predetermined threshold. If the instant acceleration exceeds the predetermined threshold, the collision sensor will transmit a signal to an igniter to initiate the inflator to produce large amounts of gas into the bag body. Meanwhile, the bag body is instantly expanded. When the car collision occurs, the driver and the front passenger (hereinafter referred to occupants) will firstly contact the inflated airbags rather than directly impact the steering wheel or the dashboard with their heads or chests, so as to achieve the purpose of protecting the occupants.
Various kinds of airbags have been developed, such as the airbags deployed from the steering wheels, the airbags deployed from the dashboards, the airbags deployed from the side windows, the airbags deployed from the seat belt buckles, and the airbags deployed from the headrests of the seats. The different kinds of airbags are expected to cope with different kinds of car collisions respectively. Each of the different kinds of airbags is nothing more than providing an inflated bag body for occupants to firstly contact, so as to buffer the occupants from other hard objects in the vehicles.
When the bag body of an airbag is instantly inflated to full deployment, the saturation pressure of the gas in the bag body makes the bag body relatively hard. A conventional airbag is a simple structure having a single bag body, so when a car collision occurs, an occupant will directly contact the hard bag body and thus injure the contacting portions of the body of the occupant.